chancroid vs herpes simplex

chancroid

noun
  • A sore characteristic of this infection. 

  • A sexually transmitted infection, caused by bacteria of species Haemophilus ducreyi, characterized by painful sores on the genitalia. 

herpes simplex

noun
  • A viral disease caused by Human herpesvirus 1 or Human herpesvirus 2 in genus Simplexvirus. 

How often have the words chancroid and herpes simplex occurred in a corpus of books? (source: Google Ngram Viewer )